NOTE: When adding useful contributons to this thread, please just batch a few programs into one single post, so that future referals to a certain program mentioned in the thread are easier to follow.
Also please ONLY add freeware programs!
A freeware data recovery program for deleted files.
http://officerecovery.com/freeundelete/
Add a prefix or suffix to your filenames, Replace a string in your filenames, Cut characters from your filenames, Change the extension of your files, Convert your filenames to uppercase, lowercase, first letter uppercase etc., Add a counter to your filenames (file01.dat, file02.dat, file03.dat, ...), Add a file attribute (creation date, file size, ...) to your filenames, Import new filenames from a text file...
http://www.fauland.com/af5.htm
A software tool which you can use to determine what process on your system has a particular file open. This is important, for example, if you want to copy or delete a file and you don't know why it isn't working.
http://www.mstsoftware.com/cFreeware.aspx
Basically erases all the meta-data from JPG files that is not needed for display of the image data. Saved me many MB of HD space.
http://www.rainbow-software.org/programs.html#JPG%20Cleaner
Scans your images and then compares them based on configurable algorithms to determine whether they are duplicates. Afterwards, you can choose to delete the duplicates manually, semi-automatically or automatically. This thing takes a lot of time to go through a lot of pics, but it might just be worth it for you.
http://www.prismaticsoftware.com/Utility/Utility.html
Ever suddenly realized that you've lost a gig of harddrive space, but never knew what was using it, only to later find out that windows had reactivated "hibernation" or that you had a 700MB temp file just sitting there, tucked away in your temp directory? Don't lie. This program shows the contents of your drives in a very easy-to-understand display and will let you track down exactly which files are using up your precious space.
http://www.win.tue.nl/sequoiaview/
Secure wiping of hard drives
http://dban.sourceforge.net/
Filecompressor. Supported file formats: 7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM, DEB. A full list of features can be found on their website.
http://www.7-zip.org/
Want a simple online harddrive? GMail Drive creates a virtual filesystem on top of your Google GMail account and enables you to save and retrieve files stored on your GMail account directly from inside Windows Explorer. GMail Drive literally adds a new drive to your computer under the My Computer folder, where you can create new folders, copy and drag'n'drop files to.
Only 120kb, very simple.
http://fileforum.betanews.com/detail/GMail_Drive/1097807577/1
Iceows
Another file extractor/compressor utility, that also integrates itself with windows. Double click a compressed file to open it, drag the contents to another folder to extract them, etc. Only supports compression for ICE, ZIP and Built-out compression for ARJ. But makes up for it with supported decompression for ICE, ARJ, ZIP, GZIP, TAR, MS-CAB, RAR, ACE, Quake 3 compressed files, Internet Mail files (Mime, UUE, XXE, B64, HQX), Java Archive (JAR, EAR, WAR), LZS, LZH, LHA, IMP, BZ2.
http://www.iceows.com/
Sling's XPSuperCleaner 2005:
del \WINDOWS\Prefetch\. /q
del \DOCUME~1\[your name here]\LOCALS~1\Temp\. /q
:)
Ah it swallowed the *.*
del \WINDOWS\Prefetch\*.* /q
del \DOCUME~1\[your name here]\LOCALS~1\Temp\*.* /qOh and DOCUME~1 is Documents and Settings.
Not sure about LOCALS~1, it doesn't even show up in a directory listing. zomg secret directories.
But there sure is a lot of crap in that Temp after a while.
apparently it's "Local Settings"